Question: A researcher is Recent research indicates that the effectiveness of antidepressant medication is directly related to the severity of the depression (Khan, Brodhead, Kolts, & Brown, 2005). Based on pre-treatment depression scores, patients were divided into four groups based on their level of depression. After receiving the anti-depressant medication, depression scores were measured again and the amount of improvement was recorded for each patient. The following data are similar to the results of the study:

a). Do the data indicate significant differences among the four levels of severity? Test with α = .05.